AN election watchdog last night admitted an embarrassing blunder when it emerged that thousands of leaflets explaining how to vote by proxy in the referendum for a regional assembly had been sent out to voters only hours before the deadline to register.

The Electoral Commission last night blamed a problem at the printers for the gaffe, which has meant large numbers of the 1.9 million leaflets arrived on doorsteps around the region yesterday morning - only hours before the 5pm deadline and long after many voters had left for work.

The exact extent of the problem is not yet known, although The Northern Echo has been made aware of problems in Wear Valley, Durham City and Sunderland. Although some leaflets reached voters on Tuesday, others are expected to be delivered this morning - more than 12 hours after the deadline has expired.

The leaflet spells out how voters can get a proxy vote to take part in the referendum if they are unable to vote themselves - for example if they are in hospital or on holiday. It also explains how to have votes redirected if they have moved address since the Electoral Register was compiled.

The Electoral Commission last night stressed that the leaflet was only one part of a broader campaign of news releases, newspaper and broadcast advertising.

"We have had some printing difficulties and that is why they have not been issued on time," said a spokeswoman.

Doubts were raised last month as to whether a flawless vote could be delivered after a report by the Electoral Commission itself suggested there were potential problems with all postal ballots, but said the referendum was too far advanced to be postponed.

Several people, including some in Durham City and the village of Castle Eden, are yet to receive a copy of the Your Say leaflet, which the Office of the Deputy Prime Minister said was being sent to every home in the region to explain the issues in the referendum.

Last night, a spokesman for the Regional Returning Officer, based in Sunderland, said printing of the 1.9 million ballot papers, the first of which will be delivered to the Royal Mail on Sunday, was progressing on schedule.